DiverDurf, you said that your wife is afraid that she would "slow your down". I can relate to her feelings, because I stared diving when I met my boyfriend, who has 1000+ dives. The first dives were certainly not great for either of us, but once I started getting the hang of things we were able to dive together without problems. Now I am able to keep up with him on almost all his dives, (even though my skills arent as developed as his, obviously) and have developed enough physical strenth to carry around my own gear, which wasnt the case during the first few months.
That said I know of a couple where he dives, she refuses. This is simply not an issue for them: sometimes she goes on the boat, sometimes not. And he'll soemtimes take afternoon off from diving to go sightseeing, whatever. It was discussed a long time ago, and they have no problems with it.